This might be the last record-breaking year for U.S. cash held overseas.

A new report from Moody’s Investors Service Inc. expects offshore cash reserves to expand 8% to $1.4 trillion by the end of 2017. That’s nearly three-quarters of all cash projected to make it into U.S. non-financial company coffers by year end.

The record-setting run-up in foreign cash could end in 2018 if Congressional Republicans advance their effort to overhaul the U.S. tax system, and the new rules come into effect next year.

The House tax bill, passed last week, would impose a one-time rate of 14% on existing foreign profits if they’re held as offshore cash. The Senate bill, which is expected to face a vote after Thanksgiving, proposes a 10% tax rate on offshore cash.

“Clearly, if there’s an incentive to repatriate the money, the offshore cash will come down,” said Richard Lane, senior vice president at Moody’s and an author of the report. “But if there’s no permanent tax reform, that offshore cash will build up again.”

Cash and liquid investments held by U.S. non-financial companies are projected to increase 5% by the end of the year to $1.9 trillion, according to the report.

The five largest cash holders are Apple Inc., Microsoft Corp., Alphabet Inc., Cisco Systems Inc. and Oracle Crop., and their cash holdings are pegged to rise 16%. The group is projected to hold $594 million overseas by year end, up from $512 in 2016.

“A lot of their business is conducted offshore, and because of current tax policy in the U.S. it is not deemed economic to repatriate those monies,” Mr. Lane said.

In the case of Apple, Oracle and Microsoft in particular, the three companies have been active in the U.S. debt market as they borrowed money to fund dividends and share buybacks, Mr. Lane said.

“Those companies in the past few years have issued more and more debt to effectively synthetically repatriate offshore cash and support dividends and share buybacks,” he said.

Spokeswomen from Oracle and Microsoft declined to comment. Representatives from Apple, Alphabet and Cisco did not immediately return requests for comment.